While the Viper's various aerodynamic features are great for hurtling around the racetrack—the ACR creates more than 1700 pounds of peak downforce—they also result in a very high drag coefficient of .541. For comparison, a Prius, one of the slipperiest production cars ever made, has a coefficient of .24.

As an example of just how much drag the ACR creates, Reece mentioned that Ralph Gilles—the man behind the newest generation of the Viper, former president and CEO of SRT, and current head of design for Fiat Chrysler—saw a noticeable drop in his efficiency whenever he started towing his personal ACR on his open-air trailer. How great is that?

Gilles saw a difference of 2 mpg between towing his Viper GTS (pictured above) and the ACR.
Ralph Gilles

Since then, this amusing fact has been bouncing around my skull, so I sent Gilles a message to follow-up. He quickly got back to me and not only confirmed the story, but provided a few more details along with some pictures.

"I tow with my EcoDiesel Grand Cherokee, which normally would get 20-21mpg towing my GTS, and got 18-19 towing the ACR," he wrote. "I am in the process of fashioning a simple device that stalls the rear wing (fills in the top)."